That is a head scratcher! I've never heard of anything like that! I'm tempted to ask what wheels you're running but it really doesn't matter at this point, does it? Does this happen on both wheels?
I think I would peen those corners or even grind them to provide clearance, It wouldn't weaken them functionally - to provide clearance and then order a set of adjustable upper wishbones from Lotus Supplies, r.d., or Dave Bean (my suspicion is that Lotus Spares would be the most economical). The problem would be solved and you'd have a camber adjustment.
Another option is to get some spacers for the wheels to move them away from the wishbones. In either case, I would do the bare minimum of grinding, peening, or spacing to do the job.
Edit: On second thought, peening is not really practical.